What is the Difference Between Adenohypophysis and Neurohypophysis

The key difference between adenohypophysis and neurohypophysis is that adenohypophysis is the anterior lobe of the pituitary gland that regulates physiological processes, such as stress, growth, reproduction, and lactation, while neurohypophysis is the posterior lobe of the pituitary gland that regulates physiological processes like coordinating fluid balance and reproductive actions.

The pituitary is the major endocrine gland in the human body. It is a pea-sized gland attached to the base of the brain. It has two different lobes: anterior (adenohypophysis) and posterior lobe (neurohypophysis). Each of these two lobes of the pituitary gland has different types of cells and produces different types of hormones. Moreover, these lobes perform different functions as well.

1. Overview and Key Difference
2. What is Adenohypophysis
3. What is Neurohypophysis
4. Similarities – Adenohypophysis and Neurohypophysis
5. Adenohypophysis vs. Neurohypophysis in Tabular Form
6. Summary – Adenohypophysis vs Neurohypophysis

What is Adenohypophysis?

The adenohypophysis is the anterior lobe of the pituitary gland. In fact, it is the front lobe of the pituitary gland. This anterior pituitary lobe is bigger than the posterior pituitary lobe and hence accounts for about 80% of the total weight of the pituitary gland. This lobe has different cell clusters that make different hormones, such as corticotrophs, thyrotrophs, somatotrophs, gonadotrophs, and lactotrophs.

Adenohypophysis produces and releases over six different hormones. These hormones regulate various cellular and physiological processes such as growth, metabolism, reproduction, response to stress or trauma, and lactation. These hormones include:

Adrenocorticotropic hormone(ACTH), which stimulates the adrenal glands to produce cortisol and other hormones;
Follicle-stimulating hormone (FSH), which stimulates the testes and ovaries to produce sperm, eggs, and estrogen;
Luteinizing hormone (LH), which stimulates ovulation in women and testosterone hormone production in men;
Growth hormone (GH), which stimulates growth;
Prolactin, which stimulates breast milk production after giving birth and regulates menstrual periods, fertility, and sexual function;
Thyroid-stimulating hormone (TSH), which stimulates thyroid hormone production

Furthermore, the diseases of adenohypophysis may include hypopituitarism (underactive pituitary gland) or hyperpituitarism (overactive pituitary gland).

Adenohypophysis and Neurohypophysis - Side by Side Comparison

Figure 01: Pituitary Gland

What is Neurohypophysis?

The neurohypophysis is the smaller posterior lobe of the pituitary gland. The main function of the posterior pituitary lobe is to store and release two hormones called oxytocin and antidiuretic hormone (ADH, or vasopressin). Neurohypophysis interacts directly with the hypothalamus since the hypothalamus is the organ that produces hormones such as oxytocin and antidiuretic hormone (ADH, or vasopressin). Oxytocin affects the uterus, mammary glands, and vas deferens, while ADH affects the kidneys.

Oxytocin is involved in uterine contractions in childbirth, lactation after childbirth, human behavior, and male and female reproductive systems. On the other hand, ADH controls the body’s osmotic balance, blood pressure, sodium homeostasis, and the functioning of the kidney. Furthermore, the diseases of neurohypophysis may include hypersecretion of oxytocin or ADH and hyposecretion of oxytocin or ADH.

What are the Similarities Between Adenohypophysis and Neurohypophysis?

Adenohypophysis and neurohypophysis are two lobes of the pituitary gland.
Both lobes are connected to each other.
They have specialized cell clusters that produce hormones.
Both lobes perform important functions.
They are affected by different diseases.

What is the Difference Between Adenohypophysis and Neurohypophysis?

The adenohypophysis is the anterior lobe of the pituitary gland that regulates physiological processes such as stress, growth, reproduction, and lactation, while neurohypophysis is the posterior lobe of the pituitary gland that regulates physiological processes such as coordinating fluid balance and reproductive actions. Thus, this is the key difference between adenohypophysis and neurohypophysis. Furthermore, adenohypophysis accounts for 80% of the total weight of the pituitary gland, while neurohypophysis accounts for 20% of the total weight of the pituitary gland.

The infographic below presents the differences between adenohypophysis and neurohypophysis in tabular form for side-by-side comparison.

Summary – Adenohypophysis vs. Neurohypophysis

Adenohypophysis and neurohypophysis are two lobes of the pituitary gland. The adenohypophysis is derived from the oral ectoderm, whereas the posterior lobe is derived from the neural ectoderm. Moreover, adenohypophysis is the larger anterior lobe of the pituitary gland that regulates physiological processes, such as stress, growth, reproduction, and lactation. In contrast, neurohypophysis is the smaller posterior lobe of the pituitary gland that regulates physiological processes, such as coordinating fluid balance and reproductive actions. So, this summarizes the difference between adenohypophysis and neurohypophysis.